Apparatus for the manufacture of hollow bodies

ABSTRACT

A moulding apparatus having a two-part mould movable between a receiving station at which thermoplastics synthetic material is extruded into the mould and a release station at which a moulded hollow body is removed from the mould. This hollow body is then supported by a blowing and calibrating member before being gripped by a two-part gripper which moves the body from the release station to a transfer station in synchronism with the mould movement. The gripper parts are mounted on arms or levers supporting and/or guiding the mould parts.

The invention relates to an apparatus for the manufacture of hollowbodies, in particular bottles, containers or the like, fromthermoplastics synthetic material by the blow-moulding method, theapparatus comprising a hollow mould in two or more parts movable to andfro between a receiving station associated with the extrusion nozzle ofan extruder and a mould release station at which the hollow body isremoved from the hollow mould and a holder supporting the hollow bodyafter opening of the hollow mould, which holder may be constructed as ablowing and calibrating pin or member, a gripper being associated withthe components supporting the halves of the hollow mould fortransferring the hollow body to subsequent apparatus, the arrangementbeing such that during movement of the hollow mould between thereceiving station and the mould release station, the gripper iscorrespondingly movable between the mould release station and a transferstation.

It is an object of the invention, inter alia, to provide such apparatuswhich may be readily adapted to specific constructional or otherrequirements, which may be determined, for example, by the shape of thehollow bodies to be produced, by the method of operation, or the like.To achieve this object there should be as few drive members as possible.Furthermore, the sequence of operations of the apparatus should not bedelayed or otherwise impaired by the presence of the gripper. Inaddition, despite at least one common drive for the hollow mould andgripper, it is desired to be able to select the path of motion of thelatter and, if necessary, also the extend of the movements independentlyof that of the hollow mould.

To fulfil this object, the invention firstly proposes that the gripperparts are attached to arms, which support and/or guide the halves of thehollow mould and which may be constructed as levers. The gripper partsmay also be attached to arms serving for guiding the halves of thehollow mould in parallel. The invention also provides the possibility ofmounting the gripper parts both on the arms supporting and/or guidingthe halves of the hollow mould as well as on the arms serving forguiding them in parallel.

If the gripper parts are only supported by one arm or lever, it isappropriate or even necessary to secure them rigidly to these arms orlevers. However, this rigid mounting must not exclude the possibility ofadjustment to different sizes or shapes of the hollow body. On the otherhand, there is the possibility of mounting the gripper parts flexibly oradjustably on the arms supporting them, which arms may also moreoversimultaneously support the halves of the hollow mould.

The possibility also exists that the gripper parts are supported byseparate arms or levers, which are connected by additional arms orlevers to the components supporting the parts of the hollow mould. Theseseparate arms or levers may have a common pivot point. In this case alsothe basic advantage is ensured that the same drive may be used for thehollow mould and grippers.

Another object of the invention is concerned with the reciprocatingmotion between the receiving station and mould release station, thegripper parts being connected to the holder transmitting thecorresponding movement to the hollow mould. It is possible but notessential to make this connection rigid. The possibility also exists ofproviding separate, preferably linear guides for the gripper parts. Inthis case, the arrangement may be such that the gripper parts or thecomponents supporting them are flexibly connected to the holderstransmitting the reciprocating motion between the receiving station andmould release station to the hollow mould. This may take place, forexample, by means of rods, fish plates or the like, which are flexiblymounted both on the holder for the hollow mould as well as to thegripper parts or components supporting them. The essential advantage ofan arrangement of this type consists in that the hollow body, on the onehand, and gripper, on the other hand, carry out the reciprocating motionsimultaneously. However, the paths of movement of both parts do not haveto be absolutely the same. On the contrary, it is possible to make thepath of movement of the gripper, for example, shorter than that of thehollow mould so that, if need be, the space required for the entirearrangement becomes less. The same is true, for example, as regards theover all height of the entire arrangement. It is conceivable that themovement of the hollow mould between the two stations contains avertical components, which must also be present in the case of thegrippers when there is a direct connection of the gripper parts or thecomponents supporting them to the hollow mould. This may be avoided bythe aforementioned construction of the parts -- flexible connectionbetween the holder for the hollow mould on the one hand and gripperparts on the other hand.

As regards their opening and closing movement, the gripper parts may beconnected to the halves of the hollow mould or to the parts supportingthem or connecting them. However, the possibility also exists ofallocating an additional drive to the gripper parts for the opening andclosing movements, for example, in the form of a pneumatic or hydrauliccylinder. In this case, the drive for the reciprocating motion betweenthe two stations is derived from the hollow mould or the holdersupporting it.

Another possibility for the transmission of the opening and closingmovements to the gripper parts consists in providing one or more cranksfor the latter, projections of the gripper parts or the componentssupporting them engaging said cranks.

According to a further aspect of the invention, stops may be provided inthe region of the end positions of the gripper parts, which stopsco-operate with swingably mounted control parts associated with thegripper parts, which control parts move the gripper parts into the openor closed position depending on the sequence of movement between bothstations. Thus, the gripper parts may be connected by elbow levers toholders supporting the former, one of the levers being respectivelyconnected to a control part actuated by the stop. In this case also aseparate drive is not necessary either for the reciprocating movementsnor for the opening and closing movements of the gripper parts. On thecontrary, all movements of the latter is derived from the drive of thehollow mould or halves of the hollow mould.

Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying drawings, in which:

FIG. 1 is a side view of an apparatus for manufacturing hollow bodies ofthermoplastics synthetic material by the blowing method and showing thehollow mould in the mould release station,

FIG. 2 is a section on line II--II of FIG. 1, but with the hollow mouldlocated in the receiving station, and

FIGS. 3 to 9 show further embodiments corresponding to FIG. 2.

The embodiments illustrated in the drawings are further developments ofthe apparatus according to British Patent Specification No. 1193050 andBritish Patent Application No. 42024/72.

In the embodiment according to FIGS. 1 and 2, two rods 11, 12 aremounted on a machine frame 10, on which rods a carriage 13 is guided tomove back and forwards. A hollow mould 14 is located on the front end ofthis carriage 13 with the interposition of means to be described, whichhollow mould consists of two halves 14a, 14b. The reciprocating movementof the carriage 13 in the direction of arrows 15, 16 is effected by abrake motor 17, the shaft 18 of which is connected to the carriage 13 bya crank 19 and a connecting rod, which engages a pin 21 on the carriage13. However, other drive means may be used for the carriage, for examplea drive roller.

The machine frame 10 also supports an extruder 22, which is providedwith a reversing extrusion head 23. Mounted in front of the latter is ablowing and calibrating member 24, which may be moved up and down bymeans of a piston guided in a cylinder 25. The cylinder 25 is supportedby a platform 26, which may simultaneously serve as a holder for anyadditional apparatus. A conveyor path 27 is located on the platform 26,which conveyor path receives the finished hollow bodies 28 andtransports them away after they have been removed from the hollow mould14.

The platform 26 is, in turn, supported by the two rods 11, 12. The twomould halves 14a, 14b are secured to clamping plates 29a, 29b, each ofwhich is provided externally with a projection 30a, 30b. A double-armedlever 31 is pivotally secured to or flexibly mounted on each of the twoprojections 30a, 30b, the axis of rotation passing at right angles tothe plane in which the carriage 13 moves to and fro. The double-armedlevers 31 are pivotally mounted on pivot pins 32 on the carriage 13. Onearm 33 of each lever 31 is pivotally or flexibly connected to the end ofan intermediate lever 34. The two other ends of this intermediate lever34 are pivotally or flexibly connected to a common drive lever 35, whichis pivoted at 35 on the carriage 13. This pivot pin 36 may extend intothe pin 21 with which the connecting rod 20 of the brake motor 17engages.

The levers 31 supporting the clamping plates 29a, 29b and thus the mouldhalves 14a, 14b are provided with extensions 37a, 37b extending beyondthe projections 30a, 30b, which extensions, at their free ends, supportparts 38a, 38b, together forming a gripper. The arrangement is such thatwhen the hollow mould is located below the blowing member 24 accordingto FIG. 1, the gripper 38a, 38b extends into the end of the conveyorpath 27 (transfer station) adjacent the hollow mould 14. The conveyorpath consists of two adjacent strips 39, the upper surfaces of whichserve to support the hollow bodies, and of lateral guide rods 40 or thelike.

Also associated with the carriage 13 is a pneumatic cylinder 41, whosepiston engages via its piston rod a joint bolt 43 to which is connectedone of the two intermediate levers 34 and the drive lever 35. Actuationof the piston in its cylinder 41 results in a closing or openingmovement of the arms of the levers 31 supporting the mould halves 14a,14b and the gripper parts 38a, 38b through the intermediary of thelevers 35 and 34. The two halves 14a and 14b of the hollow mould and thegripper parts 38a, 38b are also moved.

Additional levers 44 are provided for guiding the halves of the hollowmould 14a, 14b in parallel, which levers 44 are each pivotally connectedat both its ends to the corresponding projection 30a, 30b and to thecarriage 13.

The apparatus illustrated in FIGS. 1 and 2 of the drawing operates suchthat a pre-form is extruded from the extrusion head 23 preferablycontinuously, which pre-form is received by the hollow mould 14. Thelatter is thus located below the extrusion head 23 in the receivingstation due to the carriage 13 with the hollow mould 14 havingpreviously been moved in the direction of arrow 16 into the right handend position. The hollow mould 14 is thus opened. Both halves 14a, 14b,of the hollow mould are separated and assume the position shown in FIG.2. The hollow mould 14 is then closed around the pre-form, which ispreferably tubular, hanging from the reversing extrusion head 23, assoon as the latter has the necessary length and is then moved in thedirection of arrow 15 into the second end position illustrated in FIG. 1of the drawings, in which it is located in the station below thecylinder 25 and the associated blowing and calibrating member 24, whichat this time assumes its upper end position. Then, i.e. after thearrival of the hollow mould at the station below the blowing andcalibrating member 24 (mould release station), the latter is moveddownwards, its free end being inserted, in customary manner, into theupper end of the tubular section located in the hollow mould. Thenand/or thereafter, the expansion of the pre-form takes place bysupplying a pressure medium through the member. After adequate coolingof the hollow body thus produced in the hollow mould, the hollow mould14 is opened by separating the two halves 14a, 14b of the mould and isreturned towards the right, i.e. in the direction of arrow 16, to thereceiving station. The previously produced hollow body is now suspendedfrom the blowing and calibrating member 24, which projections from aboveinto the opening, i.e., for example, into the bottle neck of the hollowbody.

The gripper parts 38a, 38b are now placed around the hollow bodysuspended from the pin 24 in the mould release station and grip thelatter, when the hollow body located in the receiving station is closedaround the pre-form suspended from the extrusion head 23 due to pivotingof the levers 31 and closure of the halves 14a, 14b of the hollow mouldeffected by this movement. When the closing operation is completed, ifthe hollow body is held by the grippers 38a, 38b, the pin 24 is removedin an upwards direction from the hollow body. Consequently, at the timeof the subsequent movement of the hollow mould 14 in the direction ofarrow 15 from the receiving station to the mould release station and ofthe gripper 38a, 38b from the mould release station to the transferstation at the beginning of the conveyor path 27, the hollow body 28 iscarried along by the gripper 38a, 38b and transferred to the conveyorpath 27, the forwards movement along this conveyor path 27 beingeffected by means of the hollow bodies inserted one after the other bythe gripper 38a, 38b into the conveyor path 27. At the left hand end ofthe conveyor path 27, and located therebelow, is a pipe 45 (FIG. 1),which receives the hollow bodies falling downwards from the conveyorpath 27 and delivers them to any subsequent stations.

Since the gripper parts 38a, 38b are rigidly mounted on the extensions37a, 37b of the levers 31, they have a different movement to the twohalves 14a, 14b of the hollow mould, in which the levers 44 have aparallel guiding action. Compared with this, during the opening andclosing movements, the two gripper parts 38a, 38b are tilted towardseach other.

The latter is also true for the embodiment according to FIG. 3, whichhas the essential parts of the embodiment according to FIGS. 1 and 2.The gripper parts 138a, 138b are supported by extensions 147a, 147b ofthe levers 144 serving to guide the halves 114a, 114b of the hollowmoulds in parallel. The transmission of movements carried out by thehollow mould halves 114a, 114b to the gripper parts 138a, 138b, is thusthrough the projections 130a, 130b, of the clamping plates 129a, 129b.

In the embodiment according to FIG. 4, both the levers 231 transmittingthe opening and closing movements as well as the levers 244 serving toguide in parallel are provided with extensions 237a, 237b or 247a, 247band the two gripper parts 238a, 238b, like the hollow mould halves 214a,214b are provided with projections 248a, 248b, on which theafore-mentioned extensions flexibly engage. This construction has theresult that, in the course of the opening and closing movements, eventhe gripper parts 238a, 238b retain a position in which they areparallel to each other, these movements however, occuring on a largerradius than those of the two hollow mould halves 214a, 214b so that theopening angle of the two gripper parts 238a, 238b is also greater thanthat of the two hollow mould halves 214a, 214b. In this case also, likethe two earlier embodiments, the same support and drive members areprovided for the hollow mould halves and gripper parts.

The gripper parts 338a, 338b of the embodiment according to FIG. 5 aresupported by separate arms 349a, 349b, the connection between these armsand the gripper parts being rigid. The arms 349a, 349b have a commonpivot point 350, which is located on the carriage 313. The actuating andguide means for the two hollow mould halves 314a 314b correspond tothose of the embodiment according to FIGS. 1 and 2 with the exception ofthe extensions 37a, 37b of the double-armed levers 31. Moreover, in theembodiment according to FIG. 5, guide members 351a, 351b are providedbetween the arms 349a, 349b and the hollow mould halves 314a, 314b orthe parts supporting them and by which the opening and closing movementsare transmitted to the gripper parts 338a, 338b. During the opening andclosing movements the latter are tilted towards each other, whereas themould halves, as in the other embodiments, retain their positionparallel to each other. Although separate arms are provided for thegripper parts 338a, 338b, here again only one drive is necessary bothfor the hollow mould halves and for the gripper parts.

The parts of the arrangement according to FIG. 6 for bringing about theopening and closing movements of the hollow mould halves 414a, 414b andthus guiding the latter correspond to those of the embodiment accordingto FIG. 5. Fixed support members 453 are provided for the gripper parts438a, 438b on the carriage 413. The projections 430a, 430b located onthe clamping plates 429a, 429b are provided with additional couplingmembers 454a, 454b, which engage holders 455a, 455b supporting thegripper parts 438a, 438b. By means of these coupling members the closingand opening movements of the hollow mould halves 414a, 414b are alsotransmitted to the gripper parts 438a, 438b.

The embodiment according to FIG. 7 corresponds in its basic constructionwith that according to FIG. 6. However, the coupling members aremissing. In place of the latter, the opening and closing movements ofthe gripper parts are brought about by hydraulic or pneumaticcylinder-piston arrangements 557a, 557b. The latter may be supported byguides 553 or secured in some other appropriate manner.

In the embodiment according to FIG. 8, separate stationary guides 659are provided for the gripper parts 638a, 638b, which guides are arrangedindependently of the carriages 613 supporting the hollow mould halves614a, 614b. Carriages 660 are mounted to move to and fro on these guides659, which carriages in turn have guides for the holders 655a, 655bsupporting the gripper parts 638a, 638b. In the course of the openingand closing movements of the gripper parts 638a, 638b, the holders 655a,655b are moved at right angles to the longitudinal guides 659.

The reciprocating motion of the gripper taking place in the direction ofarrows 615 and 616 between the mould release station in which thefinished hollow body is received and the transfer station in which thegripper releases the hollow body is transmitted by the carriage 613 tothe gripper. For this purpose, guide rods 661 are provided which producethe connection between the carriage 613 and the gripper parts.

The opening and closing movements are transmitted by a cam 662a, 662b tothe gripper parts 638a, 638b respectively. For this purpose, the holders655a, 655b are provided at their ends remote from the gripper parts withrollers 663a, 663b or the like which engage in the respectivelyassociated cam. During passage over the cam section 664a, 664b, thegripper is closed. In the open position of the gripper parts 638a, 638b,the cam section 665a, 665b are traversed. At the transition pointsbetween both cam sections, stops 666 are located which allow the rollers663a, 663b to pass solely in the direction of the arrows. The particularadvantage of the embodiment according to FIG. 8 consists in that thereciprocating movements in the direction of arrows 615, 616 carried outby the grippers 638a, 638b do not have to coincide unconditionally withthe corresponding movements of the carriage 613 and the hollow mouldsupported by the latter. On the contrary, owing to the flexible mountingof the parts 661 producing the connection between the carriage 613 andgrippers 638a, 638b, it is possible, for example, to allow the grippersto carry out linear movements, whereas the hollow mould carries outcircular movements. It is also possible to allow the grippers 638a, 638bto carry out movements in a horizontal plane, whereas the hollow mouldis moved to and fro at an angle to the horizontal. In any case, due tothis the area in which the movements of all parts takes place, may bereduced and in particular in the horizontal and/or the vertical planes.Moreover, the embodiment according to FIG. 8 is particularly suitablewhen only a small distance is necessary for the closing and openingmovements of the gripper. This is true for example if the gripper parts638a, 638b solely grip the neck of a bottle which generally has a smalldiameter.

The embodiment according to FIG. 9 corresponds in its basic constructionto that according to FIG. 8. The two gripper parts 738a, 738b are guidedindependently of the hollow mould and its support members which are notshown in the drawing. In this case the movements between the individualstations in the direction of arrows 715, 716 are likewise transmitted byguide rods 761. Consequently, the advantages described for theembodiment according to FIG. 8 are obtained, in particular thepossibility of choosing a movement for the gripper which is differentfrom that of the hollow mould.

The opening and closing movements are transmitted to the two gripperparts 738a, 738b by elbow levers. A pair of elbow levers 770a and 771aor 770b and 771b is associated with each gripper part. In this casegripper parts 738a and the associated elbow levers 770a, 771a are shownin the open position and the gripper part 738b with associated elbowlevers 770b, 771b are shown in the closed position. The elbow levers770a, 771a or 770b, 771b of each gripper part are connected to eachother by a cross-bar 772a, 772b. At the joints 773a, 773b of the elbowlevers the cross-bars engage the latter. The actuation of the elbowlevers is effected by radial arms 773a, 773b, which, at pivot points774a, 774b of an elbow lever which does not alter its position, engagethe arm of the elbow lever mounted at this point so that it does notrotate. These arms co-operate with stops 775a, 775b and 776a, 776b,which are associated with the end positions of the gripper 738a, 738bwith respect to the reciprocating movements in the direction of arrows715 and 716.

Although, due to the different positions in which the two gripper parts738a, 738b are shown in the drawing, a clear definition of the positionof the gripper with respect to the reciprocating movement in thedirection of arrows 715, 716 is not possible, FIG. 9 shows that theclosing and opening movements of the gripper parts 738a, 738b areachieved in that the arms 773a, 773b strike against the stops 775a, 775bor 776a, 776b during the closing stage of the movements and theresulting tilting of these arms is transmitted to the gripper parts by acorresponding actuation of the elbow levers 770a, 771a and 770b, 771b.In this case it is also true that the same drive system is used for thegrippers and the hollow mould.

Separate guides, similar to the guides 659 of FIG. 8, independent of thehollow mould and the parts supporting it are provided for the grippers738a, 738b. The stops 775a 775b and 776a, 776b may be supported by theseguides not shown in FIG. 9.

In contrast to the embodiments of FIGS. 1 to 8, FIG. 9 shows a gripperwhich is suitable for receiving five hollow bodies simultaneously. Theassociated hollow mould will also be provided with a correspondingnumber of moulding pockets.

In the aforedescribed embodiments it is assumed that the blowing andcalibrating member is associated with the mould release station so thatthe blowing up of the pre-form to form the finished hollow body alsotakes place in this station.

Naturally, other constructions are possible, for example the blowingmember or other part necessary for the supply of pressure medium mayfollow the reciprocating movement of the hollow mould between thereceiving station and the mould release station. In this case, in themould release station a separate holder for the or each hollow body isprovided in order to guarantee its position until it is gripped by thegripper. This is also true if the part located in the mould releasestation for the supply of the pressure medium is constructed such thatit cannot support the hollow body. This could be the case, for example,with a needle through which the pressure medium is supplied.

We claim:
 1. Apparatus for the cyclical manufacture and transport ofblow molded hollow bodies from thermoplastic material comprising hollowmold members, gripper means, both said hollow mold members and saidgripper means being movable between an open and closed position, meansmounting said hollow mold members and said gripper means for movement ofsaid hollow mold members between a parison receiving station, and a moldreleasing station simultaneous with movement of said gripper meansbetween said releasing station and a transfer station, means to expandthe parison to form a hollow body, means for moving the hollow moldmembers into an open position to release them from contact with thehollow body, a holder for supporting the hollow body after the hollowmold members are released, and means for moving said gripper means intoa closed position to engage the hollow body for transport to thetransfer station by said mounting means, both said moving means beingindependently connected to their respective hollow mold members andgripper means such that said hollow mold members and said gripper meansare movable in the open position and in the closed position relative toeach other through the action of the moving means only.
 2. Apparatus forthe cyclical manufacture and transport of blow molded bodies as claimedin claim 1, in which the means for moving the mold members are actuatedby first power means and the means for moving the gripper means areactuated by second power means.
 3. Apparatus for the cyclicalmanufacture and transport of blow molded bodies as claimed in claim 2,in which the second power means comprises a hydraulic cylinder-pistonassembly.
 4. Apparatus for the cyclical manufacture and transport ofblow molded bodies as claimed in claim 2, in which the second powermeans comprises a pneumatic cylinder-piston assembly.